Phononic Thermal Transfer in Micro/Nano Systems: From Fundamental Research to Applications by Prof Li Baowen

The IAS and SPMS at NTU jointly organised a seminar on 4 May 2023 at SPMS LT2 by Visiting Professor Li Baowen. His talk was titled “Phononic Thermal Transfer in Micro/Nano Systems: From Fundamental Research to Applications”.

Prof Li is from the Department of Materials Science and Engineering, and the Department of Physics at Shenzhen International Quantum Academy, Southern University of Science and Technology.  A prominent researcher in micro-/nanoscale thermal transport and thermal metamaterials, his group has developed novel concepts such as thermal diodes, transistors, logic gates and memory, establishing the new field of phononics. His research has been published in top journals, including Physical Review Letters and Review of Modern Physics.  Prof Li has been recognised with awards such as the Brillouin Medal (2017), National Science Award (2005) (Singapore), and Asia Achievement Award (OCPA) (2005). He is a fellow of APS and a member of the Academia Europaea.

^{Prof Li Baowen sharing his group's research work on phononic thermal conduction.}  

During the seminar, Prof Li provided a brief introduction of the fundamental questions in phononic research, including divergent thermal conductivity, the relationship between anomalous thermal conductivity and anomalous diffusion, and thermal magic angle in twisted graphene. He gave several examples to illustrate the historical and modern research progress in understanding the complex thermal behaviour and phonon transport in micro/nano systems. Additionally, Prof Li shared recent research works by his group and collaborators on phonon/heat management, such as heat control by phononic crystals, interfacial thermal resistance, and Fröhlich phonon condensation. These findings hold practical significance in Singapore and worldwide, given the growing importance of heat management in chips.

In addition to his exciting findings, Prof Li shared his research experience and offered encouragement to young students and researchers to persist in their ideas and never give up during challenging times. He emphasised that in order to achieve research progress, young scientists should "do it hard, do it fast, and do it quick" because competition in the research field is becoming increasingly challenging. Profr Li also suggested reading well-known textbooks, which could provide new insights into physics and inspire new research directions. His helpful suggestions and advice garnered applause from the audience. 

Overall, Prof Li's seminar highlighted the crucial role of phonons in macro/nano fields, from traditional thermal transport to modern on-chip thermal management, and the exciting possibilities for innovation and advancement in these areas through continued research.

^{Exciting Q&A session on phonon/heat management.}

“I enjoy this seminar very much. It contains both fundamental aspects and very recent advances. These contents are suitable for audiences ranging from undergraduates to experts in the field” – Haoran Xue (Research Fellow, SPMS)

“Prof Li's seminar is based on phononic thermal conduction. To visualise the divergent thermal conductivity in 1D and 2D systems, he used concise formulas, clear computations and experiment results in his presentation.”– Zheyu Cheng (PhD student, SPMS)

“Prof Li introduced a new understanding to the heat transfer in lower dimensional materials with its possible industrial applications, thus stimulated deeper investigations on thermal transfer different from three dimensional materials.” - Teo Hau Tian (PhD student, SPMS)

Written by Long Yang | Research Fellow, SPMS